CVE-2026-23327

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-03-25. NVD baseline CVSS 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed()

cxl_payload_from_user_allowed() casts and dereferences the input payload without first verifying its size. When a raw mailbox command is sent with an undersized payload (ie: 1 byte for CXL_MBOX_OP_CLEAR_LOG, which expects a 16-byte UUID), uuid_equal() reads past the allocated buffer, triggering a KASAN splat:

BUG: KASAN: slab-out-of-bounds in memcmp+0x176/0x1d0 lib/string.c:683 Read of size 8 at addr ffff88810130f5c0 by task syz.1.62/2258

CPU: 2 UID: 0 PID: 2258 Comm: syz.1.62 Not tainted 6.19.0-dirty #3 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xce/0x650 mm/kasan/report.c:482 kasan_report+0xce/0x100 mm/kasan/report.c:595 memcmp+0x176/0x1d0 lib/string.c:683 uuid_equal include/linux/uuid.h:73 [inline] cxl_payload_from_user_allowed drivers/cxl/core/mbox.c:345 [inline] cxl_mbox_cmd_ctor drivers/cxl/core/mbox.c:368 [inline] cxl_validate_cmd_from_user drivers/cxl/core/mbox.c:522 [inline] cxl_send_cmd+0x9c0/0xb50 drivers/cxl/core/mbox.c:643 __cxl_memdev_ioctl drivers/cxl/core/memdev.c:698 [inline] cxl_memdev_ioctl+0x14f/0x190 drivers/cxl/core/memdev.c:713 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa8/0x330 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdaf331ba79 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdaf1d77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdaf3585fa0 RCX: 00007fdaf331ba79 RDX: 00002000000001c0 RSI: 00000000c030ce02 RDI: 0000000000000003 RBP: 00007fdaf33749df R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdaf3586038 R14: 00007fdaf3585fa0 R15: 00007ffced2af768

Add 'in_size' parameter to cxl_payload_from_user_allowed() and validate the payload is large enough.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
36(Track)
EG Risk 36/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

March 25, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 4, 2026
No patch confirmed yet.
generic

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dc184ac2f0ba77ae19725ee06ad3ab36bb9d1f61
generic

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7c8a7b7f063b7e7ae9bba4cbaa14a5d2fe3a55e1
generic

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/60b5d1f68338aff2c5af0113f04aefa7169c50c2

Vendor Advisories for CVE-2026-23327(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.34—osv
linuxKernel @ 6.19.7—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 7.2~rc5-1~exp1 (335 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.2~rc5-1~exp1 (160 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (117 versions)6.19.8-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 185 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 15:01 UTCOSV refresh
  3. 2026-09-02 14:11 UTCEPSS rescore
  4. 2026-09-01 13:53 UTCEPSS rescore
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  6. 2026-08-30 19:17 UTCEPSS rescore
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  15. 2026-08-19 17:03 UTCEPSS rescore
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 14:56 UTCEPSS rescore
  18. 2026-08-16 10:25 UTCEG score recompute
  19. 2026-08-16 10:25 UTCGHSA enrichment
  20. 2026-08-16 02:14 UTCEPSS rescore
  21. 2026-08-15 01:30 UTCEPSS rescore
  22. 2026-08-14 19:35 UTCGHSA enrichment
  23. 2026-08-14 06:44 UTCEG score recompute
  24. 2026-08-14 06:44 UTCGHSA enrichment
  25. 2026-08-13 22:00 UTCEPSS rescore
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  1. 2026-08-12 20:59 UTCEG score recompute
  2. 2026-08-12 20:59 UTCGHSA enrichment
  3. 2026-08-12 13:50 UTCEPSS rescore
  4. 2026-08-11 21:01 UTCEG score recompute
  5. 2026-08-11 21:01 UTCGHSA enrichment
  6. 2026-08-11 13:42 UTCEPSS rescore
  7. 2026-08-11 04:05 UTCEG score recompute
  8. 2026-08-11 04:04 UTCGHSA enrichment
  9. 2026-08-11 00:00 UTCEPSS rescore
  10. 2026-08-10 06:22 UTCGHSA enrichment
  11. 2026-08-09 18:19 UTCEG score recompute
  12. 2026-08-09 18:19 UTCGHSA enrichment
  13. 2026-08-09 13:46 UTCEPSS rescore
  14. 2026-08-09 06:20 UTCEG score recompute
  15. 2026-08-09 06:20 UTCGHSA enrichment
  16. 2026-08-08 16:37 UTCEPSS rescore
  17. 2026-08-08 04:35 UTCGHSA enrichment
  18. 2026-08-07 16:36 UTCGHSA enrichment
  19. 2026-08-06 19:01 UTCEG score recompute
  20. 2026-08-06 19:01 UTCGHSA enrichment
  21. 2026-08-06 13:46 UTCEPSS rescore
  22. 2026-08-06 01:05 UTCEG score recompute
  23. 2026-08-06 01:05 UTCGHSA enrichment
  24. 2026-08-05 19:17 UTCEPSS rescore
  25. 2026-08-04 15:10 UTCEPSS rescore
  26. 2026-08-04 10:38 UTCEPSS rescore
  27. 2026-08-03 23:51 UTCEG score recompute
  28. 2026-08-03 23:51 UTCGHSA enrichment
  29. 2026-08-03 10:35 UTCEPSS rescore
  30. 2026-08-02 15:39 UTCEG score recompute
  31. 2026-08-02 15:39 UTCGHSA enrichment
  32. 2026-08-02 02:26 UTCEPSS rescore
  33. 2026-08-01 04:15 UTCEPSS rescore
  34. 2026-07-30 01:30 UTCEPSS rescore
  35. 2026-07-27 14:13 UTCEPSS rescore
  36. 2026-07-26 14:54 UTCEPSS rescore
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  38. 2026-07-25 14:17 UTCEPSS rescore
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  40. 2026-07-24 14:17 UTCEPSS rescore
  41. 2026-07-23 14:18 UTCEPSS rescore
  42. 2026-07-23 14:18 UTCEPSS rescore
  43. 2026-07-23 03:07 UTCEG score recompute
  44. 2026-07-22 14:08 UTCEPSS rescore
  45. 2026-07-21 15:24 UTCEPSS rescore
  46. 2026-07-21 15:24 UTCEPSS rescore
  47. 2026-07-20 17:08 UTCEPSS rescore
  48. 2026-07-19 14:31 UTCEPSS rescore
  49. 2026-07-19 14:31 UTCEPSS rescore
  50. 2026-07-18 10:04 UTCEPSS rescore
  51. 2026-07-18 10:04 UTCEPSS rescore
  52. 2026-07-17 06:46 UTCOSV refresh
  53. 2026-07-16 17:03 UTCEPSS rescore
  54. 2026-07-16 17:03 UTCEPSS rescore
  55. 2026-07-15 16:57 UTCEPSS rescore
  56. 2026-07-15 16:57 UTCEPSS rescore
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  59. 2026-07-13 22:30 UTCEPSS rescore
  60. 2026-07-12 05:46 UTCEPSS rescore
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  62. 2026-07-11 08:27 UTCEPSS rescore
  63. 2026-07-09 19:10 UTCEPSS rescore
  64. 2026-07-08 15:15 UTCEPSS rescore
  65. 2026-07-08 15:15 UTCEPSS rescore
  66. 2026-07-07 13:46 UTCEPSS rescore
  67. 2026-07-06 16:27 UTCEPSS rescore
  68. 2026-07-06 16:27 UTCEPSS rescore
  69. 2026-07-05 02:30 UTCEPSS rescore
  70. 2026-07-04 06:31 UTCEPSS rescore
  71. 2026-07-04 06:31 UTCEPSS rescore
  72. 2026-07-01 15:06 UTCEPSS rescore
  73. 2026-07-01 15:06 UTCEPSS rescore
  74. 2026-06-30 23:22 UTCEPSS rescore
  75. 2026-06-30 23:22 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-23327?
CVE-2026-23327 is a high vulnerability published on March 25, 2026. In the Linux kernel, the following vulnerability has been resolved: cxl/mbox: validate payload size before accessing contents in cxlpayloadfromuserallowed() cxlpayloadfromuserallowed() casts and dereferences the input payload without first verifying its size. When a raw mailbox command is sent with…
When was CVE-2026-23327 disclosed?
CVE-2026-23327 was first published in the National Vulnerability Database on March 25, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23327 actively exploited?
CVE-2026-23327 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.6% of all scored CVEs.
What is the CVSS score of CVE-2026-23327?
CVE-2026-23327 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-23327?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23327, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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